Experimental evidence for the influence of charge on the adsorption capacity of carbon dioxide on charged fullerenes

TL;DR

This study combines experiment and theory to demonstrate that the charge on fullerenes significantly influences their capacity to adsorb carbon dioxide, with implications for charged surface adsorption processes.

Contribution

It provides new experimental and theoretical evidence showing charge-dependent adsorption behavior of CO2 on fullerenes, highlighting the role of molecular quadrupole moments.

Findings

Highest adsorption observed with C60+ ions.

Charge significantly affects CO2 adsorption capacity.

Quadrupole moment of CO2 influences charge dependence.

Abstract

We show, with both experiment and theory, that adsorption of $CO_2$ is sensitive to charge on a capturing model carbonaceous surface. In the experiment we dope superfluid helium droplets with $C_{60}$ and $CO_2$ and expose them to ionising free electrons. Both positively and negatively charged $C_{60}(CO_2)_n^{+/-}$ cluster ion distributions are observed with a high-resolution mass spectrometer and these show remarkable and reproducible anomalies in intensities that are strongly dependent on the charge. The highest adsorption capacity is seen with $C_{60}^+$. Complementary density functional theory calculations and molecular dynamics simulations provided insight into the nature of the interaction of charged $C_{60}$ with $CO_2$ as well as trends in the packing of $C_{60}^+$ and $C_{60}^-$. The quadrupole moment of $CO_2$ itself was seen to be decisive in determining the charge dependence of the observed adsorption features. Our findings are expected to apply to adsorption of $CO_2$ by charged surfaces in general.